Most fishing hooks are formed with an eye at a first end for attachment to a fishing line and a curved portion with a sharp barb at a second end. In use, the conventional fishing hook hangs vertically down from the end of the line. A live or artificial lure is mounted on the hook to attract a fish. When a fish takes the hook, the line is pulled up to set the hook and then the fish can be reeled in.
There is a class of fish for which the conventional hooks are not generally effective. Fish such as flounder open their mouths horizontally rather than vertically. For this reason, a flounder can take a vertically suspended lure into its mouth, but not be caught.